And max232 like solutions should work for just about everyone. MAX232s require much less black-magic, like vampiring the negative voltage from the TX line.

But that's neither here nor there. If you have a handful of transistors, resistors, a diode, and a cap laying around, can replicate a transistor-based level shifter. Just follow Sparkfun's schematic. You can use pretty much any small signal transistors, I like 2N3904s and 2N3906s as the NPN/PNP respectively, but it shouldn't matter here. The unlabeled resistors should likely be either 10K or 1K.

The Arduino serial schematic contains a similar level converter, but it proved unreliable enough that both NKC and myself make MAX232 based 'duinos instead.